An X-ray diagnostic apparatus is an apparatus configured to acquire an X-ray image of a subject such as a patient by: irradiating the subject with X-rays from an X-ray irradiation unit; and detecting the X-rays that pass through the subject by use of an X-ray detector. As the X-ray diagnostic apparatus of this type, for example, there has been developed an X-ray diagnostic apparatus provided with a C-arm or the like which holds the X-ray irradiation unit and the X-ray detector in an opposed fashion, and configured to move the X-ray irradiation unit and the X-ray detector to image capturing positions for the subject on a bed, to capture an X-ray image of a region of attention of the subject, and to display the image on a monitor.
The X-ray diagnostic apparatus has a normal image capturing mode, and an X-ray irradiation mode called a fluoroscopic mode designed to consecutively display X-ray images of the subject by consecutively emitting small amounts of X-rays from the X-ray irradiation unit. X-ray images captured in the fluoroscopic mode are generally referred to as fluoroscopic images. In particular, a proposal has been made on a technique (for example, a spot imaging method) of: setting a region of interest (ROI) in a mask image which is an X-ray image; acquiring fluoroscopic images (moving images) of the region of interest by irradiating only the set region of interest with X-rays; and displaying the moving images superimposed on the mask image (still image).
The X-ray diagnostic apparatus capable of capturing the fluoroscopic images as described above is used, for example, for treating an aneurysm. An example of the aneurysm treatment is a stent-graft placement method under X-ray fluoroscopy. In the stent-graft placement method, a surgeon in an operation identifies positions and the like of branching blood vessels prior to the placement of the stent graft. To this end, the surgeon attaches a transparent sheet onto a monitor screen which is displaying the fluoroscopic images, and handwrites marks on the transparent sheet with a pen or the like.
However, when the marks are handwritten on the transparent sheet on the monitor screen as described above, the marks become useless if the image capturing position is changed. For this reason, checking from multiple image capturing positions (image capturing angles, for example) requires a troublesome task to attach another transparent sheet and handwrite marks thereon each time the image capturing position is changed. On the other hand, in the case of employing fluoroscopic road-mapping to superimpose fluoroscopic images in real time, the above-mentioned troublesome task is required again and again for checking from multiple angles.